Total Value =$23,000
Time = 10 february to 10 august = 6 months
And
Rate of discount = 9% =0.09
Now we have to find the discount on the note
So we multiply the amount , time and rate
but time should be in years
So 6 months = 6/12 years = 0.5 years
So
Discount = 23,000 * 0.5 * 0.09 = 1035
Hence total Discount = $1035